.app-header {
  background: linear-gradient(to right, var(--card-bg), #111827);
  padding: 16px 24px;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
  border-bottom: 1px solid rgba(255, 255, 255, 0.05);
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(8px);
}

.header-content {
  max-width: 1280px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.header-left {
  display: flex;
  flex-direction: column;
}

.logo-container {
  display: flex;
  align-items: center;
  gap: 12px;
}

.logo-icon {
  width: 36px;
  height: 36px;
  border-radius: 8px;
  background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-weight: bold;
  font-size: 18px;
  box-shadow: 0 2px 10px rgba(99, 102, 241, 0.3);
}

.app-title {
  color: var(--text-color) !important;
  margin: 0 !important;
  background: linear-gradient(to right, #fff, #94a3b8);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  letter-spacing: -0.5px;
}

.app-subtitle {
  color: var(--text-secondary);
  font-size: 14px;
  margin-top: 4px;
  margin-left: 48px;
}

.header-right {
  display: flex;
  align-items: center;
}

.header-button {
  color: var(--text-secondary);
  border: none;
  transition: all 0.3s;
}

.header-button:hover {
  color: var(--text-color);
  background: rgba(255, 255, 255, 0.05);
}

.premium-button {
  background: linear-gradient(to right, var(--primary-color), var(--secondary-color));
  border: none;
  border-radius: 8px;
  font-weight: 500;
  transition: all 0.3s;
  box-shadow: 0 2px 10px rgba(99, 102, 241, 0.3);
}

.premium-button:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 15px rgba(99, 102, 241, 0.4);
  background: linear-gradient(to right, var(--primary-hover), var(--primary-color));
}

/* 响应式设计 */
@media (max-width: 768px) {
  .app-header {
    padding: 12px 16px;
  }
  
  .header-content {
    flex-direction: column;
    gap: 16px;
  }
  
  .header-left {
    align-items: center;
  }
  
  .app-subtitle {
    margin-left: 0;
  }
  
  .premium-button {
    display: none;
  }
}

@media (max-width: 576px) {
  .app-title {
    font-size: 20px !important;
  }
  
  .logo-icon {
    width: 30px;
    height: 30px;
    font-size: 14px;
  }
}